Regarding wireless communication, especially in case of broadband transmission, in addition to a preceding path to be received first, there is a path that arrives delayed by way of reflection from obstacles, such as buildings or mountains, thereby causing ISI (Inter-Symbol Interference). Such environments that multiple paths arrive are called multi-path environments. In case of multicarrier transmission, such as OFDM (Orthogonal Frequency Division Multiplexing), OFDMA (Orthogonal Frequency Division Multiple Access), or MC-CDM (Multi Carrier-Code Division Multiplexing), a guard interval (GI) is added to a multicarrier time-domain signal, thereby preventing ISI due to a delayed path whose delay is within the GI. If there is a delayed path whose delay exceeds the GI, the periodicity of FFT (Fast Fourier Transform) is lost, thereby causing ICI (Inter-Carrier Interference) in addition to the ISI. Additionally, if a reception device moves at the high speed, a channel variation in one OFDM symbol is large, thereby also causing ICI. The ISI and ICI significantly deteriorate reception performance.
Non-Patent Document 1 discloses turbo equalization technology. Specifically, Non-Patent Document 1 discloses that replicas of ISI and ICI are generated based on bit log likelihood ratios (LLR) of the results of error correction decoding, and the generated replicas are cancelled from the reception signal to suppress the ISI and ICI, thereby performing suppression of ISI and ICI and optimal detection on the signal remaining after the cancelling.